<p>From an evolutionary point of view, it is difficult to explain the existence
of altruism that is not directed at kin or at friends. But humans
demonstrate this form of altruism commonly, in such ways as donating to
charity or heroically saving another's life. One explanation of these
behaviours that is still consistent with evolutionary theory is the idea that
altruism may function as a signal. Altruists gain a positive reputation
through their deeds that may ultimately return to increase their biological
fitness. Here I test this idea in a variety of ways, focusing on altruism as a
signal of status. In the laboratory, I conducted an experiment where
participants had the incentive to signal their personal wealth to others. In
another experiment, I manipulated participants' relative status in an
attempt to reduce costly conflict between participants. Outside the
laboratory, I investigated the connection between heroism and
reproductive success through a sample of WWI heroes. The background,
methods, and conclusions of these studies are detailed within.</p>